Archaeologists working in Sicily's Valley of the Temples have found traces of a settlement thought to pre-date the famous Greek temples built there in around 600 BC .

The valley near Agrigento on Sicily's southern coast is one of Europe's most important archeological sites. It marks a sacred area built when Greeks landed there to start the civilisation of Magna Grecia in southern Italy .

The discovery of a structure possibly built before the Greeks arrived came during preparatory work ahead of a project to shore up the ground near the Temple of Hera. Archaeologists uncovered a mysterious walled structure on top of which ancient Greeks had apparently built a shrine and a burial ground .

Until now it has been thought that Agrigento was settled by the Greeks soon after they began starting colonies in much of the Mediterranean in the 7th century BC .

"It has not yet been possible to establish precisely when these remains date back to," cautioned Pietro Meli, head of the agency which administrates the Valley of the Temples archaeological park .

Meli said fixing a date would be possible if and when archaeologists found pieces of clay vessels or ceramics, which would provide clear evidence .

He noted that the settlement appeared to have been built along the line of the ancient road to Gela, a town about 70 km southeast of Agrigento .

Several finds dating back to ancient Greek and early Christian times were also made recently. Experts found what appeared to be a Christian burial ground and an earlier Greek temple, digging up small statues, incense holders and lanterns .

There are eight temples, most of them well-preserved, in the Valley of the Temples. In the 5th century BC, at the height of Agrigento's power and wealth, there are said to have been 21 temples there .

"I'm sure there's still a lot waiting to be discovered," Meli said .

The present site, which draws thousands of tourists a year, was placed on the UNESCO World Heritage List in 1997 .